William J. Johnson saw danger on the beach. A retired master chief for the Coast Guard, he worried about transmission wires that were draped over a channel near James Island, Washington.

He called a district office for the Coast Guard to warn staff that plastic safety balls appeared to be missing from the wires. Johnson knew that at least one private aircraft had hit the lines before.

In 2010, a few years after Johnson’s call, a Coast Guard helicopter flew straight into those wires.

The tail section of the MH-60T Jayhawk immediately separated. The front part of the cabin vaulted over the open ocean and splashed into the water. The accident killed three crew members. Only co-pilot Lt. Lance Leone survived. Officials later blamed him for the accident, a move that has divided the Coast Guard.

The accident points to a larger pattern at the Coast Guard. Often overlooked as the fifth branch of the U.S. military, the Coast Guard has suffered a string of accidents amid questions about unsafe practices, poor oversight from leaders and a failure to respond to red flags.

Just months before the accident near James Island, a high-speed Coast Guard response craft in San Diego Bay smashed into a family boat carrying 8-year-old Anthony DeWeese and killed him. The boy’s death was a psychic blow to a military organization that prides itself on saving lives, not taking them.

Documents and accident data reviewed by The Center for Investigative Reporting reveal lapses in judgment and missed opportunities by the Coast Guard to strengthen safety standards and protect crew members and civilians.

Between 2000 and 2013, the Coast Guard witnessed dramatic spikes in accidents causing death, injury and equipment damage. During that time, 27 aviators and other personnel were killed on land, in the air and at sea. Last year, the number of recorded aviation accidents was higher than at any time since 2006.

The deadliest period was between 2008 and 2010, when 14 crew members died in aviation accidents. The loss of lives and equipment was worse than the Coast Guard had suffered in three decades.

Critics of the Coast Guard say the service must hold itself accountable for the string of accidents instead of pointing the finger at a single officer, like Leone, after a high-profile incident.

“They've had a lot of accidents, had a lot of crashes,” said Jeffrey Addicott, a St. Mary's University law professor and former military lawyer who has assisted Leone with his case. “They obviously need better training, more training – accountability for people not doing their jobs.”

In an interview from the Department of Homeland Security's headquarters, then-Coast Guard Commandant Adm. Robert Papp acknowledged a significant problem with the accidents and said the service had conducted an internal review. By the time Papp took over as the Coast Guard's top admiral in 2010, he'd already begun to worry about complacency and “slackening proficiency,” as he's called it.